"It's why perverse priests find it so easy to take advantage of them."

The outspoken lawyer said the Church of England and the Jewish faith didn't induct children until they were teenagers and they had "less of a problem".

"It may be the Australian royal commission will recommend a law that prevents a child being confirmed in a religion until they are 14," Mr Robertson said.

"That seems to me a sensible way of reducing the dangers to children. And it is a way the new pope might even grasp."

The author of The Case of the Pope: Vatican Accountability for Human Rights Abuse argues Benedict's "command responsibility" goes back to 1981 when as Cardinal Ratzinger he was appointed head of the Vatican body that disciplines errant priests.

"He will be remembered for turning a blind eye to the abuse of over 100,000 young children by paedophile priests," Mr Robertson said.

The pope's insistence that homosexuality was evil encouraged hate crimes, his attacks on the women's rights movement encouraged sexism and his opposition to liberation theology prevented the Church in Latin America and Asia fighting poverty, the lawyer added.

As a head of state Benedict enjoyed absolute immunity from legal action but that won't remain in retirement. He could now face lawsuits from victims.

"I would think it likely that some victims of priests whom he has refused to defrock, and who have gone on to commit crimes against those victims, may seek to sue him for damages for negligence," Mr Robertson said.

He wouldn't comment on whether evidence gathered during Australia's royal commission could be used in any legal action.

But he said the pope's swift action in relation to Cardinal Keith O'Brien this week "speaks volumes for his slow or non-existent actions in relation to priests against whom allegations were made in the past".